The interface area between the undersurface of a semi-trailer fifth wheel pin plate and the upper surface of a tractor fifth wheel plate must be maintained properly lubricated.
The usual practice of lubricating this interface area involves disconnecting the tractor from the semi-trailer, the application of a quantity of grease to the upper surface of the tractor trailer fifth wheel plate and the reconnection of the semi-trailer to the tractor. This operation is of course time-consuming inasmuch as not only must the tractor be uncoupled from the trailer and moved outward from therebeneath and subsequently moved back beneath and coupled to the trailer, but the landing gear of the trailer must be lowered and raised. These time-consuming operations, when added to other normal maintenance operations, are sometimes considered as excessive and skipped with the result that fifth wheel pin plates and fifth wheel plates are not properly lubricated.
In addition, if a tractor is driven over more than a short over-the-road distance to pickup a semi-trailer during inclement weather the grease upon the fifth wheel plate of the tractor can become excessively contaminated with dirt and/or sand with the result that such grease should be removed prior to coupling of the tractor to a semi-trailer. While removal of contaminated grease may be reasonably quickly carried out, the additional time which then must be spent to properly coat the fifth wheel plate with grease can be considered as excessive if a short operational time consideration is present with respect to a deadline for delivery of the semi-trailer to be trailed behind the tractor. Accordingly, in the interest of saving time contaminated grease is sometimes not removed from a tractor fifth wheel plate and replaced by new grease.
Accordingly, it may be seen that a need exists for a means whereby the grease on a tractor fifth wheel plate may be replenished either automatically or with a minimum of effort.
Various forms of fifth wheel lubricating structures and other lubricating devices including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 141,168, 1,235,812, 3,463,512, 3,598,427, 3,622,173 and 3,743,054. However, these previously known forms of lubricating devices do not incorporate the combined structure of the instant invention in operative association with a fifth wheel plate or a fifth wheel pin plate in a manner such that controlled lubrication of such plates may be effected.